1. Field of the Invention
The present invention relates to an image processing apparatus.
2. Description of Related Art
There has been known a digital multifunctional machine comprising a copy function that reads out an original image by an image reading section such as a color image scanner and generates image data based on the read out original image to output the image data by an image output section such as a color printer or a color facsimile as an output image, and a printer function that outputs image data having been input from outside from an image output section. Further, recent digital multifunctional machines generally include a scanning out function that outputs image data generated based on the read out original image to an external device such as a personal computer.
In such digital multifunctional machines, the color system is required to be converted by subjecting image data to a given conversion processing. Namely, the image reading section for reading out an original image reads out the original image with the color system of R (read), G (green) and B (blue) in which the original image is easily processed as image data, and the image output section converts the image data comprising the RGB color space into the color space of C (cyan), M (magenta), Y (yellow), and K (black) to output as an output image. On the contrarily, image data which is output to an external device by the scanning out function is generally kept in the RGB color space.
Further, in order to use the printer function, image data of the RGB color space which is input from outside is required to be subjected to CMYK color conversion which is generally carried out by a printer controller which adopts a conversion processing method different from the RGB-CMYK color conversion.
Therefore, there has been a problem that between the image data that the image data of RGB color space the image reading section read out is subjected to the CMYK color conversion by a digital multifunctional machine main body when used as the copy function, and the image data that is once scanned out to the external device and is input again in the printer controller to be subjected to the CMYK color conversion, the color reproducibility differ from each other due to the difference in their color conversion processing methods, thereby the output results of the output images differ from each other.
Although the printer controller may be incorporated into the main body of the digital multifunctional machine, the above problem will occur as long as the print controller includes the function to carry out its own RGB-CMYK color conversion.
Incidentally, as the technologies considering the color reproducibility of the image data which is once scanned out, such apparatuses have been proposed including: an apparatus for embedding color attribute information which is referred to in the color conversion into image data in addition to converting the output image into a device independent color (for example, see Patent Document 1); and an apparatus for outputting machine difference correction values together with the image data in scanning out (for example, see Patent Document 2).
[Patent Document 1] Japanese Patent Publication Laid-Open No. 2002-33901
[Patent Document 2] Japanese Patent Publication Laid-Open No. 2002-237946
However, these proposed technologies are not those considering the color reproducibility based on the two different color conversion processing methods as described above. Therefore, there has been a problem that the image qualities are not necessarily identical between that being output after an original image is read out by the image reading section and is subjected to the color conversion, and that being output after the original image is read out from the image reading section and is once output outside, and then the output image is input again from outside.